block: Add SIO scheduler
Signed-off-by: andip71 <andreasp@gmx.de> Signed-off-by: djb77 <dwayne.bakewell@gmail.com> Signed-off-by: prashantpaddune <elonpras@my.smccd.edu>
This commit is contained in:
andip71
prashantpaddune
parent
f2225b03b6
commit
b8a7393f07
|
|
@ -309,10 +309,12 @@ CONFIG_IOSCHED_CFQ=y
|
|||
CONFIG_IOSCHED_BFQ=y
|
||||
# CONFIG_BFQ_GROUP_IOSCHED is not set
|
||||
CONFIG_IOSCHED_FIOPS=y
|
||||
CONFIG_IOSCHED_SIO=y
|
||||
CONFIG_DEFAULT_CFQ=y
|
||||
# CONFIG_DEFAULT_BFQ is not set
|
||||
# CONFIG_DEFAULT_NOOP is not set
|
||||
# CONFIG_DEFAULT_FIOPS is not set
|
||||
# CONFIG_DEFAULT_SIO is not set
|
||||
CONFIG_DEFAULT_IOSCHED="cfq"
|
||||
CONFIG_ASN1=y
|
||||
CONFIG_UNINLINE_SPIN_UNLOCK=y
|
||||
|
|
|
|||
|
|
@ -39,6 +39,16 @@ config CFQ_GROUP_IOSCHED
|
|||
---help---
|
||||
Enable group IO scheduling in CFQ.
|
||||
|
||||
config IOSCHED_SIO
|
||||
tristate "Simple I/O scheduler"
|
||||
default y
|
||||
---help---
|
||||
The Simple I/O scheduler is an extremely simple scheduler,
|
||||
based on noop and deadline, that relies on deadlines to
|
||||
ensure fairness. The algorithm does not do any sorting but
|
||||
basic merging, trying to keep a minimum overhead. It is aimed
|
||||
mainly for aleatory access devices (eg: flash devices).
|
||||
|
||||
config IOSCHED_BFQ
|
||||
tristate "BFQ I/O scheduler"
|
||||
default n
|
||||
|
|
@ -95,6 +105,9 @@ choice
|
|||
config DEFAULT_NOOP
|
||||
bool "No-op"
|
||||
|
||||
config DEFAULT_SIO
|
||||
bool "SIO" if IOSCHED_SIO=y
|
||||
|
||||
endchoice
|
||||
|
||||
config DEFAULT_IOSCHED
|
||||
|
|
@ -104,6 +117,7 @@ config DEFAULT_IOSCHED
|
|||
default "bfq" if DEFAULT_BFQ
|
||||
default "fiops" if DEFAULT_FIOPS
|
||||
default "noop" if DEFAULT_NOOP
|
||||
default "sio" if DEFAULT_SIO
|
||||
|
||||
endmenu
|
||||
|
||||
|
|
|
|||
|
|
@ -20,6 +20,7 @@ obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o
|
|||
obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o
|
||||
obj-$(CONFIG_IOSCHED_BFQ) += bfq-iosched.o
|
||||
obj-$(CONFIG_IOSCHED_FIOPS) += fiops-iosched.o
|
||||
obj-$(CONFIG_IOSCHED_SIO) += sio-iosched.o
|
||||
|
||||
obj-$(CONFIG_BLOCK_COMPAT) += compat_ioctl.o
|
||||
obj-$(CONFIG_BLK_CMDLINE_PARSER) += cmdline-parser.o
|
||||
|
|
|
|||
412
block/sio-iosched.c
Normal file
412
block/sio-iosched.c
Normal file
|
|
@ -0,0 +1,412 @@
|
|||
/*
|
||||
* Simple IO scheduler
|
||||
* Based on Noop, Deadline and V(R) IO schedulers.
|
||||
*
|
||||
* Copyright (C) 2012 Miguel Boton <mboton@gmail.com>
|
||||
*
|
||||
*
|
||||
* This algorithm does not do any kind of sorting, as it is aimed for
|
||||
* aleatory access devices, but it does some basic merging. We try to
|
||||
* keep minimum overhead to achieve low latency.
|
||||
*
|
||||
* Asynchronous and synchronous requests are not treated separately, but
|
||||
* we relay on deadlines to ensure fairness.
|
||||
*
|
||||
*/
|
||||
#include <linux/blkdev.h>
|
||||
#include <linux/elevator.h>
|
||||
#include <linux/bio.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/init.h>
|
||||
#include <linux/version.h>
|
||||
#include <linux/slab.h>
|
||||
|
||||
enum { ASYNC, SYNC };
|
||||
|
||||
/* Tunables */
|
||||
static const int sync_read_expire = HZ / 2; /* max time before a sync read is submitted. */
|
||||
static const int sync_write_expire = 2 * HZ; /* max time before a sync write is submitted. */
|
||||
|
||||
static const int async_read_expire = 4 * HZ; /* ditto for async, these limits are SOFT! */
|
||||
static const int async_write_expire = 16 * HZ; /* ditto for async, these limits are SOFT! */
|
||||
|
||||
static const int writes_starved = 2; /* max times reads can starve a write */
|
||||
static const int fifo_batch = 8; /* # of sequential requests treated as one
|
||||
by the above parameters. For throughput. */
|
||||
|
||||
/* Elevator data */
|
||||
struct sio_data {
|
||||
/* Request queues */
|
||||
struct list_head fifo_list[2][2];
|
||||
|
||||
/* Attributes */
|
||||
unsigned int batched;
|
||||
unsigned int starved;
|
||||
|
||||
/* Settings */
|
||||
int fifo_expire[2][2];
|
||||
int fifo_batch;
|
||||
int writes_starved;
|
||||
};
|
||||
|
||||
static void
|
||||
sio_merged_requests(struct request_queue *q, struct request *rq,
|
||||
struct request *next)
|
||||
{
|
||||
/*
|
||||
* If next expires before rq, assign its expire time to rq
|
||||
* and move into next position (next will be deleted) in fifo.
|
||||
*/
|
||||
if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist)) {
|
||||
if (time_before(next->fifo_time, rq->fifo_time)) {
|
||||
list_move(&rq->queuelist, &next->queuelist);
|
||||
rq->fifo_time = next->fifo_time;
|
||||
}
|
||||
}
|
||||
|
||||
/* Delete next request */
|
||||
rq_fifo_clear(next);
|
||||
}
|
||||
|
||||
static void
|
||||
sio_add_request(struct request_queue *q, struct request *rq)
|
||||
{
|
||||
struct sio_data *sd = q->elevator->elevator_data;
|
||||
const int sync = rq_is_sync(rq);
|
||||
const int data_dir = rq_data_dir(rq);
|
||||
|
||||
/*
|
||||
* Add request to the proper fifo list and set its
|
||||
* expire time.
|
||||
*/
|
||||
rq->fifo_time = jiffies + sd->fifo_expire[sync][data_dir];
|
||||
list_add_tail(&rq->queuelist, &sd->fifo_list[sync][data_dir]);
|
||||
}
|
||||
|
||||
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,38)
|
||||
static int
|
||||
sio_queue_empty(struct request_queue *q)
|
||||
{
|
||||
struct sio_data *sd = q->elevator->elevator_data;
|
||||
|
||||
/* Check if fifo lists are empty */
|
||||
return list_empty(&sd->fifo_list[SYNC][READ]) && list_empty(&sd->fifo_list[SYNC][WRITE]) &&
|
||||
list_empty(&sd->fifo_list[ASYNC][READ]) && list_empty(&sd->fifo_list[ASYNC][WRITE]);
|
||||
}
|
||||
#endif
|
||||
|
||||
static struct request *
|
||||
sio_expired_request(struct sio_data *sd, int sync, int data_dir)
|
||||
{
|
||||
struct list_head *list = &sd->fifo_list[sync][data_dir];
|
||||
struct request *rq;
|
||||
|
||||
if (list_empty(list))
|
||||
return NULL;
|
||||
|
||||
/* Retrieve request */
|
||||
rq = rq_entry_fifo(list->next);
|
||||
|
||||
/* Request has expired */
|
||||
if (time_after(jiffies, rq->fifo_time))
|
||||
return rq;
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static struct request *
|
||||
sio_choose_expired_request(struct sio_data *sd)
|
||||
{
|
||||
struct request *rq;
|
||||
|
||||
/*
|
||||
* Check expired requests.
|
||||
* Asynchronous requests have priority over synchronous.
|
||||
* Write requests have priority over read.
|
||||
*/
|
||||
rq = sio_expired_request(sd, ASYNC, WRITE);
|
||||
if (rq)
|
||||
return rq;
|
||||
rq = sio_expired_request(sd, ASYNC, READ);
|
||||
if (rq)
|
||||
return rq;
|
||||
|
||||
rq = sio_expired_request(sd, SYNC, WRITE);
|
||||
if (rq)
|
||||
return rq;
|
||||
rq = sio_expired_request(sd, SYNC, READ);
|
||||
if (rq)
|
||||
return rq;
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static struct request *
|
||||
sio_choose_request(struct sio_data *sd, int data_dir)
|
||||
{
|
||||
struct list_head *sync = sd->fifo_list[SYNC];
|
||||
struct list_head *async = sd->fifo_list[ASYNC];
|
||||
|
||||
/*
|
||||
* Retrieve request from available fifo list.
|
||||
* Synchronous requests have priority over asynchronous.
|
||||
* Read requests have priority over write.
|
||||
*/
|
||||
if (!list_empty(&sync[data_dir]))
|
||||
return rq_entry_fifo(sync[data_dir].next);
|
||||
if (!list_empty(&async[data_dir]))
|
||||
return rq_entry_fifo(async[data_dir].next);
|
||||
|
||||
if (!list_empty(&sync[!data_dir]))
|
||||
return rq_entry_fifo(sync[!data_dir].next);
|
||||
if (!list_empty(&async[!data_dir]))
|
||||
return rq_entry_fifo(async[!data_dir].next);
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static inline void
|
||||
sio_dispatch_request(struct sio_data *sd, struct request *rq)
|
||||
{
|
||||
/*
|
||||
* Remove the request from the fifo list
|
||||
* and dispatch it.
|
||||
*/
|
||||
rq_fifo_clear(rq);
|
||||
elv_dispatch_add_tail(rq->q, rq);
|
||||
|
||||
sd->batched++;
|
||||
|
||||
if (rq_data_dir(rq))
|
||||
sd->starved = 0;
|
||||
else
|
||||
sd->starved++;
|
||||
}
|
||||
|
||||
static int
|
||||
sio_dispatch_requests(struct request_queue *q, int force)
|
||||
{
|
||||
struct sio_data *sd = q->elevator->elevator_data;
|
||||
struct request *rq = NULL;
|
||||
int data_dir = READ;
|
||||
|
||||
/*
|
||||
* Retrieve any expired request after a batch of
|
||||
* sequential requests.
|
||||
*/
|
||||
if (sd->batched > sd->fifo_batch) {
|
||||
sd->batched = 0;
|
||||
rq = sio_choose_expired_request(sd);
|
||||
}
|
||||
|
||||
/* Retrieve request */
|
||||
if (!rq) {
|
||||
if (sd->starved > sd->writes_starved)
|
||||
data_dir = WRITE;
|
||||
|
||||
rq = sio_choose_request(sd, data_dir);
|
||||
if (!rq)
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* Dispatch request */
|
||||
sio_dispatch_request(sd, rq);
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
static struct request *
|
||||
sio_former_request(struct request_queue *q, struct request *rq)
|
||||
{
|
||||
struct sio_data *sd = q->elevator->elevator_data;
|
||||
const int sync = rq_is_sync(rq);
|
||||
const int data_dir = rq_data_dir(rq);
|
||||
|
||||
if (rq->queuelist.prev == &sd->fifo_list[sync][data_dir])
|
||||
return NULL;
|
||||
|
||||
/* Return former request */
|
||||
return list_entry(rq->queuelist.prev, struct request, queuelist);
|
||||
}
|
||||
|
||||
static struct request *
|
||||
sio_latter_request(struct request_queue *q, struct request *rq)
|
||||
{
|
||||
struct sio_data *sd = q->elevator->elevator_data;
|
||||
const int sync = rq_is_sync(rq);
|
||||
const int data_dir = rq_data_dir(rq);
|
||||
|
||||
if (rq->queuelist.next == &sd->fifo_list[sync][data_dir])
|
||||
return NULL;
|
||||
|
||||
/* Return latter request */
|
||||
return list_entry(rq->queuelist.next, struct request, queuelist);
|
||||
}
|
||||
|
||||
static int sio_init_queue(struct request_queue *q, struct elevator_type *e)
|
||||
{
|
||||
struct sio_data *sd;
|
||||
struct elevator_queue *eq;
|
||||
|
||||
eq = elevator_alloc(q, e);
|
||||
if (!eq)
|
||||
return -ENOMEM;
|
||||
|
||||
/* Allocate structure */
|
||||
sd = kmalloc_node(sizeof(*sd), GFP_KERNEL, q->node);
|
||||
if (!sd) {
|
||||
kobject_put(&eq->kobj);
|
||||
return -ENOMEM;
|
||||
}
|
||||
eq->elevator_data = sd;
|
||||
|
||||
spin_lock_irq(q->queue_lock);
|
||||
q->elevator = eq;
|
||||
spin_unlock_irq(q->queue_lock);
|
||||
|
||||
/* Initialize fifo lists */
|
||||
INIT_LIST_HEAD(&sd->fifo_list[SYNC][READ]);
|
||||
INIT_LIST_HEAD(&sd->fifo_list[SYNC][WRITE]);
|
||||
INIT_LIST_HEAD(&sd->fifo_list[ASYNC][READ]);
|
||||
INIT_LIST_HEAD(&sd->fifo_list[ASYNC][WRITE]);
|
||||
|
||||
/* Initialize data */
|
||||
sd->batched = 0;
|
||||
sd->fifo_expire[SYNC][READ] = sync_read_expire;
|
||||
sd->fifo_expire[SYNC][WRITE] = sync_write_expire;
|
||||
sd->fifo_expire[ASYNC][READ] = async_read_expire;
|
||||
sd->fifo_expire[ASYNC][WRITE] = async_write_expire;
|
||||
sd->fifo_batch = fifo_batch;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void
|
||||
sio_exit_queue(struct elevator_queue *e)
|
||||
{
|
||||
struct sio_data *sd = e->elevator_data;
|
||||
|
||||
BUG_ON(!list_empty(&sd->fifo_list[SYNC][READ]));
|
||||
BUG_ON(!list_empty(&sd->fifo_list[SYNC][WRITE]));
|
||||
BUG_ON(!list_empty(&sd->fifo_list[ASYNC][READ]));
|
||||
BUG_ON(!list_empty(&sd->fifo_list[ASYNC][WRITE]));
|
||||
|
||||
/* Free structure */
|
||||
kfree(sd);
|
||||
}
|
||||
|
||||
/*
|
||||
* sysfs code
|
||||
*/
|
||||
|
||||
static ssize_t
|
||||
sio_var_show(int var, char *page)
|
||||
{
|
||||
return sprintf(page, "%d\n", var);
|
||||
}
|
||||
|
||||
static ssize_t
|
||||
sio_var_store(int *var, const char *page, size_t count)
|
||||
{
|
||||
char *p = (char *) page;
|
||||
|
||||
*var = simple_strtol(p, &p, 10);
|
||||
return count;
|
||||
}
|
||||
|
||||
#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
|
||||
static ssize_t __FUNC(struct elevator_queue *e, char *page) \
|
||||
{ \
|
||||
struct sio_data *sd = e->elevator_data; \
|
||||
int __data = __VAR; \
|
||||
if (__CONV) \
|
||||
__data = jiffies_to_msecs(__data); \
|
||||
return sio_var_show(__data, (page)); \
|
||||
}
|
||||
SHOW_FUNCTION(sio_sync_read_expire_show, sd->fifo_expire[SYNC][READ], 1);
|
||||
SHOW_FUNCTION(sio_sync_write_expire_show, sd->fifo_expire[SYNC][WRITE], 1);
|
||||
SHOW_FUNCTION(sio_async_read_expire_show, sd->fifo_expire[ASYNC][READ], 1);
|
||||
SHOW_FUNCTION(sio_async_write_expire_show, sd->fifo_expire[ASYNC][WRITE], 1);
|
||||
SHOW_FUNCTION(sio_fifo_batch_show, sd->fifo_batch, 0);
|
||||
SHOW_FUNCTION(sio_writes_starved_show, sd->writes_starved, 0);
|
||||
#undef SHOW_FUNCTION
|
||||
|
||||
#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
|
||||
static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
|
||||
{ \
|
||||
struct sio_data *sd = e->elevator_data; \
|
||||
int __data; \
|
||||
int ret = sio_var_store(&__data, (page), count); \
|
||||
if (__data < (MIN)) \
|
||||
__data = (MIN); \
|
||||
else if (__data > (MAX)) \
|
||||
__data = (MAX); \
|
||||
if (__CONV) \
|
||||
*(__PTR) = msecs_to_jiffies(__data); \
|
||||
else \
|
||||
*(__PTR) = __data; \
|
||||
return ret; \
|
||||
}
|
||||
STORE_FUNCTION(sio_sync_read_expire_store, &sd->fifo_expire[SYNC][READ], 0, INT_MAX, 1);
|
||||
STORE_FUNCTION(sio_sync_write_expire_store, &sd->fifo_expire[SYNC][WRITE], 0, INT_MAX, 1);
|
||||
STORE_FUNCTION(sio_async_read_expire_store, &sd->fifo_expire[ASYNC][READ], 0, INT_MAX, 1);
|
||||
STORE_FUNCTION(sio_async_write_expire_store, &sd->fifo_expire[ASYNC][WRITE], 0, INT_MAX, 1);
|
||||
STORE_FUNCTION(sio_fifo_batch_store, &sd->fifo_batch, 0, INT_MAX, 0);
|
||||
STORE_FUNCTION(sio_writes_starved_store, &sd->writes_starved, 0, INT_MAX, 0);
|
||||
#undef STORE_FUNCTION
|
||||
|
||||
#define DD_ATTR(name) \
|
||||
__ATTR(name, S_IRUGO|S_IWUSR, sio_##name##_show, \
|
||||
sio_##name##_store)
|
||||
|
||||
static struct elv_fs_entry sio_attrs[] = {
|
||||
DD_ATTR(sync_read_expire),
|
||||
DD_ATTR(sync_write_expire),
|
||||
DD_ATTR(async_read_expire),
|
||||
DD_ATTR(async_write_expire),
|
||||
DD_ATTR(fifo_batch),
|
||||
DD_ATTR(writes_starved),
|
||||
__ATTR_NULL
|
||||
};
|
||||
|
||||
static struct elevator_type iosched_sio = {
|
||||
.ops = {
|
||||
.elevator_merge_req_fn = sio_merged_requests,
|
||||
.elevator_dispatch_fn = sio_dispatch_requests,
|
||||
.elevator_add_req_fn = sio_add_request,
|
||||
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,38)
|
||||
.elevator_queue_empty_fn = sio_queue_empty,
|
||||
#endif
|
||||
.elevator_former_req_fn = sio_former_request,
|
||||
.elevator_latter_req_fn = sio_latter_request,
|
||||
.elevator_init_fn = sio_init_queue,
|
||||
.elevator_exit_fn = sio_exit_queue,
|
||||
},
|
||||
|
||||
.elevator_attrs = sio_attrs,
|
||||
.elevator_name = "sio",
|
||||
.elevator_owner = THIS_MODULE,
|
||||
};
|
||||
|
||||
static int __init sio_init(void)
|
||||
{
|
||||
/* Register elevator */
|
||||
elv_register(&iosched_sio);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void __exit sio_exit(void)
|
||||
{
|
||||
/* Unregister elevator */
|
||||
elv_unregister(&iosched_sio);
|
||||
}
|
||||
|
||||
module_init(sio_init);
|
||||
module_exit(sio_exit);
|
||||
|
||||
MODULE_AUTHOR("Miguel Boton");
|
||||
MODULE_LICENSE("GPL");
|
||||
MODULE_DESCRIPTION("Simple IO scheduler");
|
||||
MODULE_VERSION("0.2");
|
||||
|
||||
Loading…
Reference in New Issue
Block a user